1. Field of the Invention
The present invention relates to a navigation system that executes a route search by using statistical traffic information.
2. Description of Related Art
A navigation system may be capable of executing a route search operation and a required traveling time calculation by taking into consideration traffic congestion conditions based upon traffic information. However, while the route search operation and the required traveling time calculation are executed based upon the traffic information available at the time of the route search operation, the congestion conditions may change significantly while the vehicle is en route. Japanese Laid Open Patent Publication No. 2008-96445 discloses a technology whereby traffic information collected in the past is accumulated as statistical data, statistical data for individual links are extracted in correspondence to specific traffic information collection conditions having been selected, changes in the congestion conditions corresponding to various time points are superimposed over a map on display and a search for a shortest route is executed with accuracy.
In addition, while the congestion conditions are bound to change as time passes following the time point at which the traffic information is obtained, an accurate search for a recommended route may be executed based upon statistical traffic data collected in the past, which correspond to a specific category of day, e.g., a weekday or a holiday, as disclosed in Japanese Laid Open Patent Publication No. 2004-239741.